Are SATA II hard drives backward compatible with SATA I controllers?

SATA-2 hard drives are backwards compatible with SATA-1 controllers. The same is also true with SATA-2 controllers and SATA-1 drives. However, if you have any difficulty with drive detection using a SATA-2 drive on a SATA-1 controller, install a jumper across pins 5-6 to limit the drive to SATA-1 speeds.